Strictly speaking bastles are a form of fortified farmhouse, usually fairly roughly built, rectangular and 15th and 16th century in date (Mainly late 16th century and some continued to be built well into the 17th century) confined to the Northern counties, only occasionally with any active defensive features (such as gun ports). However, a few very similar type buildings exist in southern Pembrokeshire and have a similar function against pirates, as would some Cornish Bartons. (Barbary pirates from North Africa were active in Southern English waters in the 15th to 17th centuries and often raided inland kidnapping individuals for slavery or later ransom. Irish pirates were active in the Irish Sea from at least the 3rd century onwards).